Process of making molding compositions from urea



Patented Sept. 1, 1936 UNE'E'ED STATS FFEQE ersr PROCESS OF MAKINGMOLDHNG COMPO- SETIONS FROM UREA No Drawing. Original application July10, 1929,

Serial No. 377,331. Divided and this application November 9, 1935,Serial No. 49,024. In

Germany September 2 Claims.

According to the process described in the application Serial No. 334,601filed January 23, 1929 now Patent 1,996,087 molded articles can 1 bemanufactured from urea or its derivatives and 5 aldehydes by causingthese components to react in a dry state. The process consists in themixing in a ball mill or other suitable device of urea, solid polymericaldehydes such as paraformaldehyde, and suitable organic or inorganicfilling bodies such as cellulose, cellulose derivatives, wood flour,asbestos, kaolin, graphite etc. until an intimate, homogeneous mixtureis obtained, thereupon molding articles from the mixture under hot pressconditions in the manner known in the art. As a modification describedin that application for example 100 parts by weight of urea, 100 partsof paraformaldehyde, 200 parts parts of lithopone, 100 parts of paperpulp and 50 parts of phenol-formaldehyde resin are mixed under heat inthe kneading machine until a mass is obtained which is brittle whencooled. The mass is ground and hot pressed. I have found that it ispossible and advantageous to manufacture the molded articles in such away that the condensation between urea and solid polymeric aldehydes iscarried out in the presence of molten organic compounds, particularlycompounds not capable of hardening or more difiicultly capable ofhardening than condensation products from urea and formaldehyde. Afterthe condensation the molding is carried out by pressing and applyingheat simultaneously or subsequently. My invention relates to suchprocess and, furthermore to new molding mixtures manufactured asdescribed hereafter.

As molten organic compounds natural or artificial resins, both thosecapable and those incapable of hardening such as colophony, copal,condensation products from monoor polyhydric phenols, glycerine ester ofphthalic acid etc. may be used. The condensation products may be used aswell in the form of resols as of resitols. Furthermore other organiccompounds may be used, such as hydrocarbons, for instance anthracene,naphthalene, hydrogenated or nitrated naphthalenes, amines etc. which donot adversely influence the course of the reaction and the properties ofthe products formed. The substances 50 may also be used mixed with oneanother. Besides substances may be used such as hydrogenated orchlorinated hydrocarbons which act as plastifiers, such as chlorinatednaphthalene. The condensation between urea and aldehydes may also becarried out in the presence of liquid,

high boiling organic compounds which give to the final product aflexible character.

Furthermore I have found that the reaction between urea and solidpolymeric aldehydes may be accelerated or retarded respectively byadding suitable contact substances. It may for instance be desirable toretard the course of the reaction if it is desired to keep the reactionmass thinly liquid for a longer time for the purpose of adding muchporous or fibrous filling material in order to give to the mixture abetter flowing capacity. In such case basic substances, such as ammonia,calcium hydroxide, hexamethylene tetramine or basic salts such ascarbonate of sodium or such like, are added to the reaction mass. Theacceleration of the course ofthe reaction and of the hardening on theother hand may be brought about by addition of acids or acid salts suchas citric acid, acetic acid, hydrochloric acid, urea nitrate etc.Several accelerating or retarding contact agents may also be used mixedwith one another, or several contact substances successively. Thequalities of the molding mixtures, for example the time or thetemperature for molding or the flowing capacity are affected by theadmixture of the different contact agents.

Example 1 1 kilo of glycerine ester of phthalic acid is fused in asuitable manner and a mixture of 4 kilos of lithophone, 1 kilo of woodflour, 2 kilos of urea and 1.6 kilos of paraformaldehyde added thereto.The fusion is continued until a mass is obtained which is brittle whencooled. Such mass is then disintegrated and molded under hot pressconditions. Thereby articles are obtained which are fast to light, havea great strength and a high polish.

Esc'ample 2 1 kilo of glycerine ester of phthalic acid is fused in asuitable manner and mixed with a mixture of 4 kilos of lithopone, 1 kiloof wood flour, 2 kilos of urea, 1.6 kilos of paraformaldehyde and 5 g.of nitrate of urea. The fusion is continued until a mass is obtainedwhich is brittle when cooled, thereupon grinding the mass and pressingit under heat.

By a suitable choice of medium in which the condensation is carried out,it is possible to increase considerably the chemical, physical andmechanical resistance of the molded articles. The present process hasthe further advantage that valuable products may be obtained in a shortoperation without any process of distillation and without any specialcare and that considerably less quantities of formaldehyde are used thanare otherwise required. 1.5 mols of formaldehyde to each mol. of ureaare sufficient for the manufacture of products of high resistance. Byusing suitable filling bodies such as paper, asbestos, lithoponearticles of white color and fast to light may be manufactured. By usingfibrous filling substances the mixing with condensation productspreferably must be carried out under heat in a kneading machine, or onmixing rollers or in other suitable devices. The molded articles may becolored, cheapened, improved or otherwise infiuenced by adding suitablefilling bodies.

Before, during, or after, the condensation, that is to say at anysuitable stage of the manufacture, aldehyde binding substances, waterbinding substances, dye-stulfs or filling bodies of any kind may beadded to the reaction mass.

Instead of urea also its derivatives such as thiourea or acetyl urea andinstead of paraformaldehyde other suitable solid polymeric aldehydessuch as trioxymethylene, polyoxymethylene may be used. The terms ureaand solid aldehydes used in this specification relate to all suchcompounds. The present invention is neither limited to the use of ureanor to the use of paraformaldehyde and is furthermore not limited to thequantities indicated as examples and to the special 7 process of mixing,molding and hardening as described above. The term filling bodies asused in this specification comprises likewise the dyestuffs,plasticizing agents and the other usual additions.

This application is a division of U. S. application Serial No. 377,331filed July 10, 1929.

I claim:

1. Process of preparing a composition suitable for molding including aresinous reaction product of a urea with a non-aqueous aldehyde as a"bonding agent which comprises fusing a glycerine ester of phthalic acidof fusible character that is solid at room temperature and less readilyhardenable by heat than the condensation product of the urea with thealdehyde, adding to the fused ester a urea and a non-aqueous aldehyde,including a filler in the fused mass, maintaining the fused conditionuntil a product is obtained that is brittle when cold, cooling anddisintegrating the cooled mass.

2. Resinous product of the urea type suitable for molding comprisingthat obtained by the condensation of a urea with a non-aqueous aldehydein the presence of a fluxing agent comprising a glycerine ester ofphthalic acid solid at room temperature and less readily hardenable byheat than the urea condensation product.

OTTO siissENGUTH.

